This application is entitled to the benefit of and incorporates by reference essential subject matter disclosed in International Patent Application No. PCT/DE99/02289 filed on Jul. 26, 1999 and German Patent Application No. 19839225.7 filed on Aug. 28, 1998.
The invention relates to a matrix printer using interchangeable ink container and having a means for preventing operation of the printer with an improper ink container.
A matrix printer of this type, designed as an inkjet printer, is disclosed by the document EP 0 606 047 A2. Its print head has a relatively small supply volume for ink, which is connected via a flexible connecting line to an interchangeable container which contains a larger ink supply. The printing ink is led out of the interchangeable container, through the connecting line, into the supply volume of the print head. As a result, the inkjet printer can carry out print jobs with very high ink consumption without the printing operation being interrupted to refill the supply volume or to replace the print head.
Although the known inkjet printer starts a printing operation even when no interchangeable container is connected to the supply volume in the print head, in this case there is the risk that particularly long print jobs will be carried out only incompletely and/or erroneously and will therefore have to be repeated.
U.S. Pat. No. 5,506,611 describes an inkjet printer and an interchangeable ink container that can be operated therein. In order to verify the proper arrangement of the ink container inside a holder belonging to the printer, inter alia a reporting system is proposed which is constructed as follows: provided on the printer is a shaft-like holder, into whose clear space a projection projects. Provided on the upper side of the ink container is an opening which is closed by a displaceable cover. When the ink container is inserted into the holder, the cover is held back by the projection, so that the opening in the upper side of the ink container is opened as the ink container is inserted further into the holder. This releases the pivoting path of a flag which, being driven by a spring, swings out of the ink container and penetrates into a forked light barrier. The latter reports the presence of an ink container in the printer to a printer control system.
A further drawback is that an interchangeable container with ink unsuitable for the operation of the inkjet printer can also be inserted into the holder, and makes the print head unserviceable or damages it permanently.
DE 91 16 990 U1 has therefore proposed to apply to the surface of an ink container a pattern of lines which connects two contacts arranged on a container holder when the ink container is put correctly into the container holder. The making of contact is reported to a control unit, which for its part enables the printing operation. In the case of this arrangement, it is also disadvantageous that, by means of the improper connection of the contacts, it is possible to feign a proper ink container which, however, contains an ink which is unsuitable for the printer. On the other hand, in the event of relatively long use of one and the same ink container, oxidation of the pattern of lines and of the contacts can occur.
U.S. Pat. No. 5,506,611 describes an inkjet printer and an interchangeable ink container that can be operated therein. In order to verify the proper arrangement of the ink container inside a holder belonging to the printer, inter alia a reporting system is proposed which is constructed as follows: provided on the printer is a shaft-like holder, into whose clear space a projection projects. Provided on the upper side of the ink container is an opening which is closed by a displaceable cover. When the ink container is inserted into the holder, the cover is held back by the projection, so that the opening in the upper side of the ink container is opened as the ink container is inserted further into the holder. This releases the pivoting path of a flag which, being driven by a spring, swings out of the ink container and penetrates into a forked light barrier. The latter reports the presence of an ink container in the printer to a printer control system.
It is the object of the invention to configure a matrix printer of the type mentioned at the beginning, and an interchangeable container for printing ink to be used with said printer, in such a way that the printing operation can be enabled or blocked reliably if no interchangeable container, or an unsuitable one, is inserted into the holder.
This object is achieved by a matrix printer having the features of claim 1. Advantageous developments of the invention are specified in the dependent claims.
In order to block and enable the printing operation, the matrix printer according to the invention has a signal transmitter and a signal receiver, which are formed on the holder, and also a signal transmitting device which is arranged on the interchangeable container. The receipt of an enable signal, emitted by the signal transmitter, by the signal receiver is interrupted as long as the interchangeable container having the signal transmitting device is not inserted into the holder. The printing operation remains blocked and is enabled only when the signal transmitting device of the interchangeable container, when the container is inserted completely into the holder, passes on the enable signal to the signal receiver.
The invention therefore firstly ensures that the printing operation is enabled only when an interchangeable container having the above-described equipment is inserted into the holder. Secondly, an interchangeable container without the signal transmitting device cannot be operated with the matrix printer. In this way, the matrix printer is therefore simultaneously protected against the use of an interchangeable container with unsuitable printing ink, which does not have the signal transmitting device.
There is interaction between a signal input, a signal transmitting device and a signal output. The arrangement of signal input and signal output is made in such a way that the enable signal can be transmitted from the signal transmitter to the signal receiver on the holder. This arrangement makes the signal transmitting device particularly robust against external influences. In addition, the inkjet printer and the interchangeable container, as a result of the precisely defined mutual arrangement of signal transmitter and signal input, on the one hand, and signal output and signal receiver, on the other hand, and also a corresponding arrangement and configuration of the signal transmission element, bear additional features which protect against the use of unsuitable interchangeable containers.
It is advantageous that the signal transmitting device in the interchangeable container is mounted separately from the ink supply. As a result, it is protected against possible damaging effects of the printing ink, and otherwise necessary devices for sealing the interchangeable container at the signal input and at the signal output are dispensed with.
The use and transmission of a mechanical enable signal provides a particularly simple and robust embodiment of the inkjet printer and of the interchangeable container. In this connection, a mechanical signal is understood to mean a symbol transmitted by the transport of movement energy or potential energy in a system of coupled mechanical components and having a specific significance. The signal transmitter protrudes from a side of the holder that faces the interchangeable container, engages in the signal input of the interchangeable container when the latter is inserted and comes into contact with a transmission element which can be moved counter to spring force. During further insertion, the transmission element is forced by the signal transmitter and counter to the spring force to execute a movement by means of which it is pressed against the signal receiver, which is a switching element which is connected to the switching device and is prestressed into an opened position. When the interchangeable container has been inserted completely into the holder, the switching element is displaced by the transmission element into a closed position, in which the printing operation is enabled. In the case of this embodiment, therefore, it is not possible to insert an interchangeable container with unsuitable printing ink completely into the holder, which firstly protects the printer and secondly indicates clearly to the operator of the printer that he is trying to insert an interchangeable container with unsuitable printing ink.
In particular, the signal transmitter can be designed as a pin and the transmission element as a pivoting lever, whose axis of rotation runs transversely with respect to the insertion direction and on whose one arm the pin acts. As a result, the pin simultaneously fulfils the task of a signal transmitter and that of a guide element as the interchangeable container is inserted into the holder. Furthermore, a different type of matrix printer, which is serviceable only with a specific different sort of printing ink, can be protected in a particularly simple way against the use of unsuitable interchangeable containers by means of a slight alteration to the position of the pin on the holder and a corresponding alteration in the arrangement of the signal input and of the pivoting lever in the interchangeable container during the production of said printer.
The matrix printer can be both an inkjet printer and a dot matrix printer. In the first case, the interchangeable container is designed as an ink container and, in the second case, as an ink ribbon cartridge. Both types of printer can be damaged by an unsuitable ink or ink ribbon impregnation. The invention offers reliable protection for both.